Pearl

Physical Properties

Hardness: 2.5 - 4.5 on Mohs scale; Color: White, cream, pink, silver; Luster: Pearly (iridescent); Crystal structure: Microcrystalline; Cleavage: None; Specific Gravity: 2.60 - 2.85

Formation & Geological History

Organic origin: Produced within the soft tissue (mantle) of a living shelled mollusk. Layers of nacre are deposited around an irritant over several years. High-quality pearls come from both saltwater and freshwater environments.

Uses & Applications

Primarily used in fine jewelry (necklaces, rings, earrings). Also used in cosmetics and traditional medicine in powdered form.

Geological Facts

Unlike most gemstones that are mined from the earth, pearls are the only gems created by living creatures. The most famous pearl in the world is probably La Peregrina, found in the 16th century.

Field Identification & Locations

Identified by its unique 'orient' or iridescence. A common field test to distinguish real pearls from plastic imitations is the 'tooth test'—real pearls feel gritty against the teeth, while fakes feel smooth.

Identified on: 5/1/2026

Mode: Standard